The inventive concept relates to semiconductor memory devices and, more particularly, to resistive memory devices and methods of writing data in resistive memory devices
Semiconductor memory devices may be classified as volatile and non-volatile in their operative natures. Non-volatile semiconductor memory devices have the advantage of retaining stored data in the absence of applied power, and have been widely used to store program code and/or data across a wide range of applications, including in particular computers and portable communication devices.
Due to continuing demand for high-capacity, low-power semiconductor memory devices, research has been conducted in certain advanced non-volatile memory devices that do not require data refresh. Advanced memory devices include, for example, the phase-change RAM (PRAM) that uses a phase-change material, the resistive RAM (RRAM) that uses a material having a variable resistive characteristic, such as a transition metal oxide, and the magnetic RAM (MRAM) that uses a ferromagnetic material. The materials used to fabricate advanced memory devices all exhibit a variable resistance property according to an applied current or voltage, and do not need to be refreshed because the materials retain said resistance property until changed.
In a resistive memory device, a unit memory cell may include a single variable resistive element and a single switching element. The variable resistive element may be connected between a bit line and the switching element, and the switching element may be connected between the variable resistive element and a word line. The resistive memory device may include a variable resistive memory cell array including individually programmable resistive memory cells.